Well, I bought lots of DRM'd LIT some years ago, to read them on my PocketPC.
I used Calibre recently to strip the DRM, and be able to convert them to MOBI or PRC in order to read them on my Cybook.
I don't have scruples about that, because I paid for them, and I don't see why I would have to buy them again in an other format...
Edit : An error here, ConvertLIT to strip DRM, then Calibre to convert into MOBI (or Mobipocket Creator to convert in PRC)